1. Field of the Invention
The invention relates to a cooling system for a generator, disposed in a chamber surrounded with running water, having a turbine; a transmission is preferably provided between the generator and the turbine.
2. Background and Relevant Information
Until now, the cooling air of the generator, which may also be under overpressure, was used directly as a heat transfer medium for removing the lost heat. Earlier versions provide single- or multi-stage blowers, among other means. The heat transmission coefficient can thus be increased so as to be adequate for the heat exchange.
The disadvantage of this arrangement is that the induced ventilation, with fans on the generator motor, is no longer adequate to overcome the resistance in these airways. Additional fans are thus needed, which already draw considerable power and are quite noisy. If this fan is built into the chamber, operation must be interrupted if the fan fails.
Another disadvantage is that only a very rough and incomplete adaption of the quantity of cooling air to the particular power loss of the generator under partial load and to the ambient temperature between summer and winter is attainable with reversible-speed fan motors and flap systems for carrying air. From the standpoint of servicing, it is also disadvantageous that in cases where the fan is disposed in the chamber, workers have to enter the high-pressure air flow.
French Patent 1267170 discloses a tubular turbine generator, the housing dome of which is embodied as a heat exchanger. However, tubular turbine systems of this kind are not worth considering until above a certain power level, which is approximately 10 MVA.
Cooling the machine directly with running water has also been attempted. However, this process is no longer possible for technical reasons, because it causes such severe water pollution.